Historically, early heating, ventilation and other types of systems employing air flow for controlling the environment of enclosed spatial areas typically comprised one or more apertures opening into the spatial area. The apertures were, in turn, located at the terminations of ducted work connected to the ventilation or heated air source. Although the apertures would often be covered with a screen or similar perforated article, the volume and directional dispersion of air into the spatial area would be dependent primarily on the existing air currents in the ducted work and spatial area, aperture size, air pressure at the aperture and the configuration of the screen perforations. Accordingly, extremely minimal selective control of air flow could be achieved.
As centralized heating and similar environmental systems (including subsequently developed air conditioning systems) became more prevalent, particularly in residential and commercial construction, it became known to install air "registers" at the ducted work apertures. The registers would often comprise fixed "slats" or similar elements to direct the air flow into the spatial area. In addition, it also became known to provide the registers with slats or like elements connected to manually operable mechanisms for moving the slats so as to adjust the quantity of open cross-sectional area of the register, thereby controlling the air flow volume. With nearly every type of forced air environmental system heretofore developed, such volumetric air flow control mechanisms have become extremely common.
As environmental control technology has become more sophisticated, and with the rapid increase in energy costs, the art of controlling air flow at locations of air flow entry into the spatial environments to be controlled has become of substantial importance. Numerous types of assemblies have been designed for controlling environmental air flow.
For example, in Douglas III, U.S. Pat. No. 4,188,862, issued Feb. 19, 1980, an assembly primarily directed to air conditioning registers of relatively small size is disclosed. The assembly includes a housing, a louver and a "closure segment" mounting shaft. A knob fits on the end of the shaft as it protrudes through a centrally located hub. A series of closure segments are mounted on the shaft for purposes of rotation relative to each other. Each closure segment is of a substantially identical triangular shape and includes an aperture at its inner shaft-engaging end. The apertures within certain of the closure segments are of a square cross-section, and adapted to receive square bosses on the shaft. Other closure segments have apertures in their shaft-engaging ends which are circular in cross-section, with a slightly larger diameter than the central portion of the shaft. Accordingly, the shaft can rotate relative to each of certain of the closure segments.
A forwardmost closure segment includes "nibs" extending downwardly from the outer circular edge of the segment. The nibs are spaced so as to be received in slots on each side of the bottommost retention member in the register louver. Accordingly, when all the closure segments are assembled on the shaft, the forwardmost segment is secured to the register louver, thus allowing the shaft to rotate relative thereto within the aperture. In a similar manner, the rearmost closure segment is secured to the shaft by means of a boss, again so that the segment rotates with the shaft. The middle closure segments are identical and mounted for rotation relative to the shaft and relative to the forwardmost and rearwardmost closure segments.
The rearwardmost closure segment includes an elongated tab extending inwardly at an angle to a radius of the shaft axis, and at an angle to the side portion of the closure segment. The outermost portion of the tab is adjacent a first side portion of the tab and the circular edge of the tab. For purposes of interconnection, the tab is raised from the outer surface of the closure segment so as to extend forwardly to the next adjacent closure segment. Certain of the closure segments have similar corresponding tabs, and certain others o the closure segments have trapezoidally-shaped recesses. The recesses have a depth slightly greater than the forward extent of the tabs so as to receive the tabs when the segments are in their assembled relationship on the shaft.
When air flow volume is desired to be at a maximum, the closure segments are positioned so that each segment axially overlaps each of the other segments. When air flow volume is desired to be decreased, the knob can be manually rotated, thereby first causing the rearmost closure segment to also be rotated in the corresponding direction. Remaining closure segments remain stationary until the tab on the rearmost segment engages the stop surface of a recess in the next adjacent closure segment. With this configuration, the register opening is slightly less than half blocked. Further rotation of the shaft causes each of the closure segments to be rotated seriatim into various configurations as shown in the Douglas III patent. The Douglas III patent can be characterized as showing a general form of volumetric air flow control.
For several reasons, technology associated with air flow environmental systems has recently become of even greater import in the construction of commercial and industrial facilities. Energy costs have caused architects, designers and facility managers to focus attention on their environmental control systems. The increasing energy costs and relatively large size of such facilities have mandated efficiency in proper delivery and dispersion of air flow. The proper dispersion of air flow is of particular concern when such facilities are controlled from a centralized source, thus often requiring heated or otherwise conditioned air to travel a substantial distance to the spatial area under control.
In addition, federal and state laws and regulations often set forth substantive restrictive requirements with respect to environmental factors, such as air quality, temperature control and the like. Further, general public attitude now prevalent in this country demands a quality work environment. Accordingly, environmental control systems must not only exhibit efficiency, but must often provide an environment relatively free of any substantial noise, drafts or other distractions. Finally, construction costs compel not only efficiency in environmental systems, but also relatively simplistic design with respect to costs of materials, ease of assembly, etc.
In many relatively modern commercial and industrial establishments, air flow is provided through ducted work above the ceilings, with the ducted work opening into the spatial areas directly through openings in the ceilings. The conventional T-bar arrangement with insulated and removable rectangular panels is an example of a ceiling construction commonly in use.
With these types of ceiling-mounted systems, the manner in which air is dispersed or "diffused" can be of primary importance with respect to efficiency and quality of environmental control of the spatial area. In these types of systems, it is not merely the volume of air flow which is important, but also the dispersion of air in directions radially from an axis perpendicular to the face of the opening which is important. For example, a ceiling-mounted air flow opening in the center of a relatively large spatial area should preferably have an air flow pattern substantially different from that which would be optimum for ceiling-mounted openings located in corners of the spatial area.
Correspondingly, however, the requirement of providing different types of air flow control registers or similar elements dependent on the intended installation location of the same would significantly increase the complexity and costs of manufacture, ordering and installation of environmental systems. Further, many of today's commercial and industrial establishments are constructed in the form of modular office systems. Such modular systems are designed to be modified as required by the facilities manager to accommodate changes such as number of office personnel, individual office sizes, functions to be performed and the like. It would be an extreme disadvantage to require movement of ceiling-mounted air flow systems in correspondence with changes in the modular configurations.
Various types of air flow control systems for use in relatively modern commercial and industrial establishments have been developed, including systems adapted for mounting in ceilings. For example, Wilson et al, U.S. Pat. No. 4,366,748, issued Jan. 4, 1983, describes an air diffuser having a deflector comprising a series of arms extending radially outward from a central hub. The deflector arms include a "bent up" portion described as enhancing the air deflection operation. The deflector is connected to a bottom perforated wall by a connection rivet through the central portion of the deflector, and through a perforation in the bottom wall. Rubber tabs are mounted between the flat portions of each arm and the perforated bottom for purposes of reducing contact, so that the deflector does not completely cover perforations under the arms. The use of the resilient tabs is described as substantially preventing vibrations from being transferred to the bottom wall, and improving air distribution by providing a small space between the deflector and the bottom wall, thereby uncovering wall perforations under the deflectors. The deflector is adjustable solely from a horizontal pattern to a downward pattern.
Kennedy, U.S. Pat. No. Re. 25,216, issued Aug. 7, 1962, describes an air distribution outlet having a frustum-shaped section flaring outwardly to a screen portion. The smaller diameter section of the frustum-shaped portion comprises a screen having a series of perforations. One embodiment of the Kennedy distribution outlet comprises an arrangement having two sets of four elements in the form of deflector strips. The deflector portions flare outwardly from a central pivot hub, and each strip is spaced 90.degree. apart from its two adjacent strips. The two strip configurations can be rotated relative to each other by removing a bolt having a spring lock nut threaded thereon.
Waeldner et al, U.S. Pat. No. 3,308,743, issued Mar. 14, 1967, discloses an air duct arrangement specifically including an extensible duct section adapted for use in a ceiling having a series of bulkheads. In one embodiment, the duct arrangement includes a telescopically arranged sleeve member capable of extension and retraction by an arm. The arrangement includes a first link connected at one end to the pivotable arm, with its other end connected to a valve assembly. The valve assembly includes a fixed hub having a link attached thereto. A set of movable vanes project radially from the hub toward the inner area of the sleeve member. An actuating rod is rotatably supported on the link and connected to the inner ends of the vanes so that the vanes can be rotated between open positions (in which they are aligned with the axis of the tubular duct) and closed positions, where the vanes are at right angles to the duct axis.
In summary, although a number of mechanisms have been developed for air flow control in environmental systems, none of these systems overcome all of the typical problems associated with such control systems, while correspondingly exhibiting particular advantages in the control of air flow patterns. Of primary importance, it is particularly advantageous to achieve specific air flow patterns, while correspondingly obtaining in an optimum manner as much "open area" as possible with respect to the face of the air flow control arrangement. To the extent an air flow control arrangement requires the face to be "covered," the volume of air flow will be reduced, thereby decreasing efficiency of operation. In addition, as the percentage of the control arrangement face being covered increases, the static back pressure within the ducted work behind the control arrangement will correspondingly increase. This build up of back pressure essentially "boot straps" a decrease in the efficiency of operation of forced air systems.
Furthermore, it is advantageous to achieve discrete and definite directional air flow patterns. It should be emphasized that such patterns are not obtained merely by a general diffusion of the air as it exits from the control arrangement. Many types of systems which purport to provide directional air flow merely serve to generate a random diffusion of the air into the spatial area. Still further, it is also advantageous to achieve the discrete and definite directional air flow pattern in radial directions relative to the face of the control arrangement. If desired air flow patterns cannot be achieved in radial directions, the efficiency of environmental control of the spatial area will be significantly reduced.
In addition to the foregoing, it is also a primary advantage to achieve a commonality of design for as many components of the air flow control arrangement as possible, notwithstanding that the control arrangement may be constructed in various sizes. Correspondingly, simplicity of instruction and relatively low material costs is also of primary importance. Finally, the adjustability of the control arrangement to provide as many distinct directional air flow patterns as possible, while still providing for relative ease of adjustment, is substantially significant.